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An earthquake early-warning system is coming to California

Angela Johnston
Barbara and Howard Hornsby stand in front of their new mobile home. Their old one was damaged in the 2014 earthquake.

Three years ago a major earthquake rattled the Bay Area. Napa Valley was hit the hardest: 200 people were injured, one person died and the total financial damage in the area was almost a billion dollars. It was also the first time an experimental early warning system called Shake Alertnotified researchers of a major quake before it actually happened. If researchers secure enough funding, we may have more time to duck, cover and hold on before the next big one.

Remembering the quake


Barbara Hornsby is a night owl, so she was awake at 3:20 a.m. when her mobile home started violently shaking side to side.

“I was sitting at a table, reading, late,” she says. She just had a moment, then went into shock. “I thought, ‘Earthquake,’” she says.

Her husband Howard was asleep in the next room.

“It started with a really loud crack, almost as if somebody had shot a gun next to you, but there was movement, too.”

Howard jolted out of bed and he heard Barbara calling for help.

“The bookcase that was three feet away from me, a six-foot-tall bookcase, fell over on me, and this was one time when it really paid off to have a very inexpensive bookcase,” she remembers.

Paperback books and little copper sculptures flew off the shelves.

“One giant thump. I said, ‘I can't get out. I’m trapped. Help!’”

Howard stumbled around in the darkness, feeling his way toward Barbara.


“The floors were separated at a large angle and there was like a three-foot gap. I could have stepped into that,” he says.

He lifted the bookcase off her legs and they made their way toward voices outside.

“It was pitch dark, no power or anything, except for flames I could see through the window,” Barbara says.

Credit Angela Johnston / KALW Public Radio
KALW Public Radio
Barbara Hornsby points to photos of the damage to her mobile home.

The earthquake ruptured the gas lines that lay underneath the mobile home park. Her neighbor's’ home was on fire.

Four homes burned to the ground that night. The Hornsbys were lucky. The fire didn’t reach their mobile home, but the earthquake broke almost all of their support beams and damaged the structure beyond repair. They decided to buy a new mobile home two blocks away.

“Everyone was just so grateful that we were all alive and well and not injured and so together ... having experienced it all together,” Barbara says.

Adding extra seconds

Some of the damage was inevitable — but the fires and Barbara’s near miss with the bookcase may have been prevented with even a few seconds of warning.


In the Napa quake, a network of sensor stations alerted researchers at the University of California, Berkeley, five seconds before people felt the shaking. The Department of Emergency Management in San Francisco, which tests the system, got a ten-second warning.

Right now there are about 600 stations sprinkled across California, with the majority in the Bay Area. But more stations means potentially faster — and more accurate — warnings.

Credit Angela Johnston
Jonah Merritt digs holes for copper grounding rods at the installation site.

U.C. Berkeley and United States Geological Survey engineers are installing one right now in Willits, a couple hours north of the Hornsby’s mobile-home park. It’s one of about 40 being built across the state over the next two years.

An earthquake sensor looks like a big black top hat. It’s placed deep inside a concrete vault, equipped with another smaller, hockey-puck-sized sensor.


Credit Angela Johnston
The vault where the sensor will live, also known as the 'snake pit.'

“We like to call it a snakepit because oftentimes we uncover everything, we find all sorts of critters down there,” says Jonah Merritt. He leads the team of engineers installing these stations across the state. Today they’re digging trenches and pounding copper rods into the soil, to ground all the electronics they’ll later be putting in the ground.

Then, they’ll wire the sensors to a big solar panel that will power the station.  

“We are recording six channels of ground motion and we will pick up earthquakes, both strong earthquakes, and tiny earthquakes, and that data will be digitized in the simplest form. We ship that data over the internet to our servers in Berkeley,” Merritt says.

Credit Angela Johnston
The earthquake sensor installed near Willits, CA.

If a minimum of four stations record movement, that means it’s not just a cow walking by, and it’s actually an earthquake. In a matter of seconds a computer will send out an alert — to police stations, emergency responders, and, researchers hope, everyone’s phones.

“This is us telling people like you, ‘Shaking is coming. Drop, cover, and hold on,’ because that’s what you need to do,” says Peggy Hellweg, who works with Merritt at the U.C. Berkeley Seismological Lab. She says, for the general public, just thinking about what you’ll do if you get an alert is one benefit of having a early warning system.


But where those extra seconds could really count is with automatic systems that could open fire station doors, start a generator, or program an elevator to stop at the nearest floor.

“Stop the trains, take the knife out of the person being operated on, maybe shut down the gas,” Hellweg says — all before the shaking even starts.

Looking to Japan

In the 2011, before the Tōhoku earthquake that caused the Fukushima nuclear disaster, Japan’s advanced early warning system alerted residents on the coast 10 to 30 seconds before they felt tremors. People in Tokyo heard alerts on cell phones, computers and TV a minute before shaking started. A semiconductor factory shut off equipment before it leaked chemicals.

Fifteen seconds before the quake hit, bullet trains received an automatic stop signal. UC Berkeley and USGS have already partnered with BART — trains will automatically slow when they get a warning — and they’ve contacted some hospitals and gas companies to suggest this may be a good thing to start thinking about.

“The more stations we have, the more quickly we can detect the earthquake, and the quicker our data loggers send the data in. The main weakness is that we don’t have enough network, enough stations throughout the state to be able to detect earthquakes as quickly as we need to,” Hellweg says.

Shaky funding

That’s why the team’s installing as many sensors as they can with the funding they have. Ideally, they want a sensor station every six miles in the whole state. That’s 600 more than we have right now. Earlier this year, President Trump slashed earthquake early warning funding from the preliminary federal budget. The House reinstated $10 million dollars — but that will only build a few hundred stations. Before the system goes public, the team needs more long-term funding.

“I hope that this is such a small number that nobody is going to say ‘Oh we have to remove that again.’ It's never for sure until the President signs the budget.”

To Hellweg, it’s a no brainer.

“It's relatively inexpensive and we get a lot of bang for our buck, so to speak. It doesn't matter if you're in a Republican district or a Democratic district, the earthquakes don't care ... to me [it's] a win-win situation,” Hellweg says.

Barbara and Howard Hornsby, the couple in the mobile home park in Napa, think so too. Barbara says she carries her cell phone on her all the time, and she knows exactly what she would’ve done if she got an alert on her phone. She’d have stepped away from the bookcase.

“Two seconds would've got me to a safer place, eight seconds we could've gone through the front door,” Hornsby says.

She says she hopes that when the next big one hits, she’ll know it’s coming before she feels it.

Angela Johnston is the Senior Producer of Uncuffed and an editor in the KALW newsroom. She holds a Master’s degree in journalism and graduated from KALW’s Audio Academy program. She’s worked for KALW in numerous roles - from the deputy news director, to the health and environment reporter, and she's covered everything from lead poisoning to climate change. Her work has aired on KALW, KQED, Reveal, and The Pulse. She also freelances as a producer and editor for Cosmic Standard and AFAR Media. Outside of work, she loves to swim in the bay, surf small waves on her longboard, read, backpack, cook, and garden.